NTP mode 7 denial-of-service vulnerability

A simple 1 byte payload spoofed UDP packet could cause a DoS between two
ntp servers. The packet will cause the two ntp servers to bounce the
information back and forth, eventually exhausting resources.

"This issue is addressed in NTP 4.2.4p8."

It is also probable that this issue affects both systems and hardward
NTP appliances.

It is recommended to update to the latest version of NTP, and to check
with any hardware vendors about possible firmware updates.